~ Captain Paul's response to: ~ Trevor ~

As I have noted in the past, Marine Digital Charts designed for on the water use do not depict the land area away from the established marine channels. This maps are based on NOAA Marine Charts which are the best in the world for defining the established marine channels that have official buoys, cans, nuns, lights and other defining markings. There are elaborate means through the Notice to Mariners to keep the positions of these Navigation Aids (NAVAID) up to date, unfortunately they do NOT represent the land features away from these marked channels.

My current NOAA Chart of Black Bay in 1:80000 scale shows a land mass named Snake Island. Those of us who travel in this area know that the island has eroded away sometime in the mid 60’s. Yet the 2009 version of that chart still shows the feature as an island.

I recommend that those who travel the southern Louisiana marshes, first consider mapping which is based on U.S.G.S Topographical maps.
Topo or “Quad” maps are designed to accurately show land features. Yes, I know you are in a boat and on the water, but look around your position. I can assure you that there is more land nearby than one of the established marine channels.

I do not know of any topo based mapping programs for your Furuno unit. I am sorry to say that the C-Map card for the Gulf of Mexico may be the best you can do. But before totaling giving up on more detailed maps for the unit, get the number and the area of coverage of your present C-Map card
and inquire to a stocking Furuno dealer to see if he could recommend a more detailed chart program for your unit. Some times, an area is broken down in to three or four sections. Each of these different cards show the a portion of the overall area, sometimes in a more detailed scale. Remember however that it may still be based on a NOAA marine chart and not on Topographical maps.

If you are looking for a very good hand held unit that can be mounted to a vehicle and connected to the boats 12volt electrical system, I would recommend the Garmin GPSMAP 62 series of hand held units. Several of these units such as those designated with a “t” ( GPSMAP 62STC and the 62st) in the model name, come preloaded with U.S, Topographical maps for the entire United States. Although they are in 1:100,000 scale they show most if not all of the many bayous, lagoons, canals, bays and lakes that make up the Louisiana marsh. But, and this is a really big BUT, they can also accommodate other Garmin topographical maps. To quote Garmin, “Adding more maps is easy with Garmin's wide array of detailed topographic, marine and road maps. With 4.3 GB of onboard memory, GPSMAP 62stc lets you conveniently download TOPO U.S. 24K maps and hit the trail, plug in BlueChart® g2 preloaded cards for a great day on the water or City Navigator NT® map data for turn-by-turn routing on roads (see maps tab for compatible maps). GPSMAP 62stc also supports BirdsEye™ Satellite Imagery (subscription required), that lets you download satellite images to your device and integrate them with your maps. In addition, the 62stc is compatible with Custom Maps, free software that transforms paper and electronic maps into downloadable maps for your device.” End.

This means that the unit can download Garmin’s aerial BirdsEye images as well as their very fine BlueChartg2 marine mapping and the very detailed topographical mapping they call TOPO US 24K. They have a micro SD card, for the GPSMAP 62st that covers the entire south east of the US in a scale of 1:24000 topo type mapping. The unit can even accommodate an on the road mapping called City Navigator. It covers the entire U.S.

Check out the unit and its mapping on the Garmin web site at www.garmin.com I believe that you can even view the available maps and zoom in on a particular area.

~ Captain Paul ~